You should always save your EndNote Library to your local directory and NOT to cloud storage e.g. your OneDrive. See:
There have been instances of EndNote Library corruption/loss of data when EndNote libraries are saved to OneDrive/cloud storage.
If you need to use your EndNote Library on more than one device or share your references/library with colleagues/friends, then you can do this by syncing with EndNote 21 (online): See:
We recommend EndNote 21 (desktop) is your 'main' library and the online version is used for syncing, for sharing references/libraries, to use on a tablet or as a backup library.
The main ways to get references into your EndNote library are:
For instructions on how to get references in to your library, see:
Regardless of how you get your references into your EndNote Library, it is important that you check your references in your library. Look out for:
Any mistakes in EndNote will mean a mistake in your Word document. If you do notice a mistake, make the correction in your EndNote Library NOT in your Word document.
You can also organise your references into 'groups'. See:
*New* for EndNote 21, you can also use the 'tagging' feature: